Indicia reading devices, also referred to as scanners, laser scanners, image readers, indicia readers, etc., typically read data represented by printed or displayed information bearing indicia, also referred to as symbols, symbologies, bar codes, etc. Barcodes, such as UPC codes, use thin and thick bar patterns to represent data while more complex coding systems, known as 2D matrix codes, use intricate patterns of blocks and arrangements to store information.
One-dimensional (1D) or linear optical bar code readers are characterized by reading data that is encoded along a single axis, in the presence and/or widths of bars and spaces, so that such symbols can be read from a single scan along that axis.
Two-dimensional (2D) or area optical bar code readers utilize a lens to focus an image of the bar code onto a multiple pixel image sensor array, which often is provided by a CMOS-based or CCD-based image sensor array that converts light signals into electric signals.
In conventional 2D imaging, the output of the 2D imaging hardware is a grid of integer values proportional to the light intensity at each pixel. For example, a point on a barcode that is in sharp focus on the sensor array results from a cone of rays (light rays having different directions) emerging from the point on the barcode, which rays are refracted by the lens, and fall on a single pixel on the sensor array. The light output value of the pixel is equal to the sum of all the rays having different directions falling onto the pixel.
A light field camera, also called a plenoptic camera, is operable to capture additional information regarding light rays having different directions emerging from a scene. One approach includes a microlens array placed in front of the sensor such that a main lens is focused on the microlens array and the microlens array is focused on the sensor array. In the light filed camera, for example, a cone of rays from a focused point in the scene that falls on a microlens of the microlens array diverts the rays to different pixels on the sensor. Another approach employs a mask instead of a microlens array. The additional information allows software algorithms to manipulate the captured image to refocus portions of the image and change the perspective or point of view of the image after the image has been captured by the imaging hardware.
There is a need for further indicia reading terminals, and more specifically, to indicial reading terminals and methods for decoding decodable indicia employing light field imaging.